Composition for engine deposit removal



United States Patent M COMPOSITION FOR ENGINE DEPOSIT REMOVAL Paul E.Oherdorfer, Jr., Devon, Wilmington, Del., assignor to Sun Oil Company,Philadelphia, Pa., a corporation of New Jersey No Drawing.Continuation-impart of application Ser. No. 476,172, July 30, 1965. Thisapplication Dec. 2, 1966, Ser. No. 598,595

9 Claims. (Cl. 252-470) ABSTRACT OF THE DISCLOSURE The presentdisclosure relates to a carburetor cleaner which cleans the internal andexternal deposits therefrom. The cleaning composition contains a cycliccarbonate inner ester as the major active component with certainsolvents, namely a C to C olefin, a mononuclear aromatic hydrocarbon anda polar solvent of an ester, glycol ether or mixtures thereof.

This application is a continuation-impart of application Ser. No.476,172, first filed July 30, 1965, by Paul E. Oberdorfer, In, and nowabandoned.

The present invention relates to removing internal and external depositsfrom fuel and air intake systems and from the combustion chambers ofinternal combustion engines.

The formation of gummy deposits on the internal and external parts ofinternal combustion engine fuel and air intake systems is an importantproblem alfecting efficient engine operation. For example, the formationof these deposits on the internal parts of a carburetor can causesticking of the automatic choke, plugging of the air bleeds, fouling ofventuri, restriction of idle air flow around the throttle blades andother conditions which adversely affect engine performance. Theformation of deposits on the external parts of a carburetor causeautomatic choke linkages, fast idle links and the like to behavesluggishly or to stick.

The formation of carbonaceous deposits on surfaces in the enginecombustion chambers is also an important problem affecting both spark,ignition and compression ignition engines. Combustion chamber depositscause increased engine wear, pro-ignition and engine knocking andincrease the octane requirement of an engine.

A composition is shown in US. Patent 2,935,479 issued to Paul E.Oberdorfer, Jr., that reduces the accumulation of deposits in enginefuel and air intake systems and in engine combustion chambers. Theactive ingredient of this composition is a cyclic carbonate inner estersuch as propylene carbonate. The cyclic carbonate inner ester loosensand dissolves engine deposits and enables the deposits to be exhaustedfrom the engine.

The present invention maintains the desirable internal cleaningproperties of the cyclic carbonate inner ester compositions but has theadditional advantage of being able to remove the external deposits onfuel and air intake systems, which removal provides two benefits: (1)improved function of the system because of the freeing of externallinkages and (2) renewed appearance of the cleaned system.

The previous compositions containing cyclic carbonate inner esters werenot capable of removing the deposits 3,382,181 Patented May 7, 1968 fromthe external parts. The internal and external deposits are of entirelydifferent types. The internal deposits are essentially polar in naturewhereas the external deposits are essentially non-polar in nature.Previous cyclic carbonate inner ester compositions suitable for cleaningthe fuel and air intake systems in a single direct application were allpolar solvents which had no effect on the external deposits.

In order to be effective for removing the polar deposits in a singleapplication the formulation must contain at least 10 volume percent ofcyclic carbonate inner esters.

The first attempt made was to dissolve the cyclic carbonate inner esterin certain hydrocarbons of the naphtha type, i.e., gasoline, since thiswould have the desirable non-polar solvent properties, however, it wasfound that the propylene carbonate was soluble in amounts up to only 1%by volume and other cyclic carbonate inner esters were soluble only inamounts up to 2% by volume. The use of gasoline per se would beunsuitable because of the danger of fire and the low solubility of thecyclic esters in gasoline, i.e., only 1 to 2%.

It was anticipated that C to C saturated aliphatic hydrocarbons would besuitable solvents for the nonpolar deposits, however, these hydrocarbonswere found to be insoluble with the carbonate inner esters. Thus neitherC to C saturated aliphatic hydrocarbons nor naphtha type materials aresuitable in the compositions of the present invention.

It was found that substituted mononuclear aromatics, particularly mixedxylenes, were miscible in all proportions with the range of cycliccarbonate inner esters employed, however, the aromatics alone were notgood enough solvents to remove the non-polar deposits.

It was found quite surprisingly that the substituted mononucleararomatics were capable of solubilizing the C to C olefins, but not thesaturated C to C hydrocarbons. The C to C saturated hydrocarbons couldnot be solubilized with the cyclic carbonate inner esters in the desiredproportions of inner ester to be employed.

It was determined that suitable mononuclear aromatic hydrocarbons werethose having from 1 to 4 substituents said substituents being selectedfrom the group consisting of hydrocarbon chains having no more than 4carbon atoms and chlorine atoms. Examples of suitable aromatic solventsinclude toluene, xylene, mesitylene, durene, ethylbenzene,1,2,3,4-t-etraethylbenzene, l-ethyl-3-isopropylbenzene, chlorobenzene,chlorotoluene, 1,2,3,4-tetrachlorobenzene and the like or mixturesthereof.

Suitable C to C olefins include, for example, hexenes, heptenes,S-methyl-l-heptene, S-methyl-l-hexene, 2,3,3,4-tetramethyl-l-pentene,Z-undecene, cyclohexene and the like or mixtures thereof.

The cyclic carbonate inner esters which are used in this invention havethe formula:

wherein each R is hydrogen or a hydrocarbon group. The hydrocarbongroups can be alkyl, aryl, aralkyl and alkaryl groups preferably havingabout 1-6 carbon atoms per group. Cyclic carbonate esters having fewercarbon atoms are generally more effective in reducing polar depositaccumulation than are esters having more carbon atoms. It is preferredthat the total carbon atoms in the hydrocarbon substituent groups notexceed about 6. The use of propylene carbonate is especially preferredin carrying out the invention. Examples of other cyclic carbonate inneresters which are suitable are ethylene carbonate, butylene carbonates,amylene carbonates, phenyl ethylene carbonate, and the like as well asmixtures of cyclic carbonate inner esters.

In the present invention the cyclic carbonate composition is applieddirectly to carburetor, internally and externally. Preferably thecleaning composition is applied from a plastic squeeze bottle or from anaerosol can using a nozzle to direct the stream of cleaner.

Cyclic carbonate inner esters are fairly viscous liquids with highsurface tension. For example, propylene carbonnate has a kinematicviscosity at 100 F. of 1.69 centistokes and a surface tension of 43.4dynes per cm. at 68 F. Thus since in the practice of this invention thedeposits are to be removed from relatively cool portions of the engine,e.g., from the upper portions of the carburetor air horn, it isdesirable to lessen the viscosity and surface tension of the cyclicester by mixture with less viscous polar organic solvents which improvethe penetration of the cyclic ester on polar deposits. It is especiallydesirable to use liquids with the cyclic carbonate esters which aresubstantially lower boiling than the cyclic esters. These last liquidsimprove the penetration of the cyclic esters in the cooler parts of theengine such as the internal 30 and external parts of the carburetorwhile in the hotter parts of the engine the solvents evaporate leavingthe cyclic esters which are most needed on these parts. The non-polarsolvents are also, for these same reasons, lower boiling than the cyclicesters. 5

Mixtures of one or more polar solvents with the cyclic esters, themononuclear aromatics and olefins can be used to increase thepenetration of the cyclic esters on the polar deposits. Suitable polarsolvents are selected from the group consisting of (1) an ester havingthe structure R ii-oR where R is hydrogen or a hydrocarbon radicalhaving 1 to 3 carbon atoms and R is a hydrocarbon radical having 1 tocarbon atoms; (2) a glycol ether having the structure where R is ahydrocarbon radical having 2 to 3 carbon atoms, R is hydrogen or ahydrocarbon radical having l to 4 carbon atoms and R is a hydrocarbonradical having 1 to 4 carbon atoms; and (3) mixtures thereof. Examplesof the polar solvents that may be used include esters such as methylformate, butyl formate, methyl acetate, ethyl acetate, propyl acetate,isopropyl acetate, amyl acetate, methyl proprionate, ethyl propionate,ethyl butyrrate, isopropyl butyrate; glycol ethers such as ethyleneether, propylene glycol diethyl ether, propylene glycol diisopropylether and the like.

Suitable cleaning compositions contain by volume 10- of a cyclic ester,5 to of a C to C olefin, 5 to of a mononuclear aromatic hydrocarbon and5 to of a polar solvent selected from the group consisting of an ester,a glycol ether and mixtures thereof.

A preferred cleaning composition is one that contains by volume a cyclicester 10-60%, a C to C olefin 5- 70%, a mononuclear aromatic hydrocarbon575%, an ester 5-75% and a glycol ether 550%. The use of the glycolethers was found (1) to increase the range of solubilities of theolefins and cyclic esters, (2) to provide a solvent of intermediatepolarity between the polar cyclic esters and the non-polarolefins and toreduce the amount of aromatic hydrocarbons necessary, for obtainingmiscibilities. Thus, by replacing a portion of the aromatic hydrocarbon,i.e., diminishing the relative proportion thereof, it is more rapidlydiminished in total concentration by evaporation during the cleaning ofthe internal parts leaving essentially polar solvents which arepreferred for the internal cleaning.

An example of a preferred composition is one containing propylenecarbonate, propylene trimer, xylene, ethyl acetate and ethylene glycolmonoethyl ether in the ranges previously mentioned.

Particularly preferred compositions according to present invention thathave been found to have excellent properties for cleaning the internaland external parts of fuel and air intake systems for internalcombustion engines as well as being relatively economical are thosecontaining by volume 15 to 35% propylene carbonate, 10 to 40% propylenetrimer, 5 to 23% mixed xylenes, 5 to 35% ethyl acetate, and 5 to 25%ethylene glycol monoethyl ether.

EXAMPLE I Eight late model automobiles that had been run on variousblends of gasoline were selected in order to test the cleaning abilityof a composition according to the present invention.

;T he composition employed was Volume percent Propylene carbonate 25Propylene trimer 25 Xylene l5 Ethyl acetate 25 Ethylene glycol monoethylether l0 TABLE I Milagc on Improvement Automobile Unelcancd CarburetorsAppearance Performance W: Tempest--.-. 0, 000 Removed residual Improvedengine idle.

varnish and gums. 64 Pontiac 4, 0 0 -....do Corrected choke operation.

Do 12, 000 -.do.. Do. 63 Chevrolet... 24, 000 .....do Improved idle andwarmup perionnanee. 130.... .dO '52 Pl mouth.-- 83, 000 .....do 62Corvair 62, 000 .....do.. Improved cold weather starting. '02 Cadillacdo glycol monomethyl ether, ethylene glycol monoethyl ether, ethyleneglycol monopropyl ether, ethylene glycol monobutyl ether, ethyleneglycol diethyl ether, ethylene glycol dibutyl ether, propylene glycolmonomethyl ether, propylene glycol monoethyl ether, propylene glycolmonobutyl 75 EXAMPLE II A 1955 Oldsmobile with over 90,000 milespresented a particular problem since its carburetor was in disrepair andthoroughly covered inside and out with varnish and oil deposits.Adjustment of the idle jets produced virtually no response in idlecharacteristics. The secondary ven turi system (4 bbl. carburetor) wasgummed up to the extent that the air bleeds were sealed shut. Theautomatic choke was gummed tight in the three-quarter closed position.The carburetor was cleaned with 8 ounces of the formulation of Example Iusing a plastic squeeze bottle and nozzle.

The idle jet pasages were cleaned by removal of the needle assembliesand squirting the formulation through the idle passages. All externalair bleeds likewise were cleaned in this fashion. The automatic chokevacuum system which had been plugged shut was cleaned by forcing astream of the formulation through the passage while the enginewas-idling. The remainder of the internal air passages were cleaned byspraying a stream of the formulation on them through the carburetorthroats, The external linkages were cleaned with the stream of cleanerand required about two ounces of the cleaner.

As a result of this cleaning operation, which was performed in situ,i.e., without removal or disassemblv of the carburetor, a vastlyimproved appearance and restoration of the carburetor to nearly originalperformance was achieved. The only part replacement necessary was arather inexpensive accelerator pump leather boot.

In order to determine the comparative effectiveness of the presentcomposition with those presently available on the market two of theleading carburetor-top engine cleaners were selected. Composition A wasfound to contain diacetone alcohol as the active ingredient, mixedxylenes as the carrier and about 1% lube oil. Composition B 2 hadethylene glycol monobutyl ether as the active ingredient, aromatichydrocarbons as the carrier and about alkyl ammonium alkyl phosphate andheavy oil. The formulation of Example I was used to demonstrate thepresent invention.

The following tests were performed.

Cleaning ability.Each formulation was sprayed on adjacent portions of aCarter Ball and Ball one-barrel carburetor which had normal depositsfrom having been run on a regular grade of gasoline, The use of a singlecarburetor eliminated variations in deposits nature from carburetor tocarburetor. The results of the test are recorded in terms of the visualobservation of the cleaning ability of each formulation.

Volatility-One ml. of each formulation was placed on a 1 /2 inch waterglass and heated to 210 F. on a steam bath. The results are recorded inhours to evaporate the sample to less than 1% of original volume andhours to dryness. Measurements of percent volume remaining at 90 and 180minutes were also made. Exceedingly fast evaporation indicatesinsufiicient time to penetrate the deposits to rinse them away.Extremely slow evaporation allows dust and dirt to build up and recreatesluggish operation. A sticky residue is undesirable since it alsorecreates the deposit problem.

Kinematic viscosity.Recorded in centistokes. Too high a viscosity (over5) prevents easy application of the cleaner formulation to the internaland external parts of the carburetor.

Surface tension.Measured in dynes/ cm. High surface tension (over 30)also inhibits the effectiveness of the cleaner.

Oil cutting-In this test the time required for /2 ml. of eachformulation to drain /2 ml. of heavy oil from a 1 ml. necked downpipette was measured. This test is designed to show the effectivness ofthe present composition to dissolve non-polar type deposits.

The results of the tests are set out in Table II.

Composition A-Gumout. Composition -BG.M. Top Engine Cleaner Gr. 8.800,#1050002.

TABLE II Composition Example I A B Test:

Cleaning Ability 5 Volatility:

Hours to 1% original volume..- 3. 0 0. 3 96. 0 Hours to Dryness 96. 0 496.0 96. 0 Percent original volume at 90 min. 1 Percent original volumeat 180 min 1 1 10 Kinematic Viscosity, Centistokes at 100 F 0.9 0.9 7. 910 Surface Tension, dyne/cm 26. 5 31. 1 30. 8

Oil Cutting, Time for ml. of solvent to drain ml. oil

1 Fast, effective. 2 Fast, partially effective. 3 Slow, partiallyeffective. 15 4 Sticky residue.

5 2 min., 27 sec. 8 3 min., 57 sec. 7 3 min., 44 sec.

Although compositions A and B performed in a satisfactory manner, it isreadily apparent that the composition according to the present inventionis superior in its cleaning ability and particularly in its ability todissolve non-polar type materials.

The use of compositions according to the present invention not onlyreduces the octane requirement of internal combustion engines andresults in more economical operation of such engines but will, alongwith proper adjustment of the engine, improve the combustion ofhydrocarbon fuels and will aid in reducing atmospheric contaminationresulting from such improper combustion.

I claim:

1. A solvent composition consisting essentially of by volume: about 10to 60% of .a cyclic carbonate inner ester having the formula wherein Ris selected from the group consisting of hydrogen, alkyl, aryl, aralkyland alkaryl hydrocarbon groups having from 1 to 15 carbon atoms pergroup, 5 to 70 of a C to cl3eole'fil'l, 5 to 75% of a mononucleararomatic hydrocarbon having from 1 to 4 substituents selected from thegroup consisting of alkyl hydrocarbon chains having 1 to 4 carbon atomsand chlorine atoms, and 5 to 80% of a polar solvent selected from thegroup consisting of (1) an ester having the structure where R ishydrogen or an alkyl hydrocarbon radical having 1 to 3 carbon atoms andR is an alkyl hydrocarbon radical having 1 to 5 carbon atoms; (2) aglycol ether having the structure R*O-R OR where R is an alkylenehydrocarbon radical having 2 to 3 carbon atoms, R is hydrogen or analkyl hydrocarbon radical having 1 to 4 carbon atoms and R is an alkylhydrocarbon radical having 1 to 4 carbon atoms; and (3) mixturesthereof.

2. A solvent composition according to claim 1 wherein the polar solventis a mixture of 5 to 75 of the ester and 5 to of the ether.

3. A solvent composition according to claim 2 wherein the cycliccarbonate inner ester is selected from the group consisting of ethylenecanbonate, butylene carbonates, amylene carbonates, phenyl ethylenecarbonate and mixtures thereof.

4. A solvent composition according to claim 3 wherein the C to C olefinis propylene trimer.

5. A solvent composition according to claim 2 wherein the ether isethylene glycol monoethyl ether.

6. A solvenlt composition according to claim 2 wherein the ether isethylene glycol monobutyl ether.

7. A solvent composition according to claim 2 wherein the mononucleararomatic hydrocarbon is chloro'benzene.

8. A solvent composition according to claim 2 wherein the cycliccarbonate inner ester is propylene carbonate, the C to C olefin ispropylene trimer, the mononuclear aromatic hydrocarbon is xylene, theester is ethyl acetate and the ether is ethylene glycol mono-ethylether.

9. A solvent composition according to claim 2 consisting essentially ofby volume: 15 to 35% propylene carbonate, 10 to 40% propylene trimer, 5to 35% xylene, 5 to 35% ethyl acetate and 5 to 25% ethylene glycolmonoethyl ether.

References Cited UNITED STATES PATENTS 5/1956 De LeW et al 252-1725/1960 Oberdorfer et a1. 252-17O

